/*
 * Copyright (c) 2016-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 */
#pragma once

#include <atomic>
#include <cassert>
#include <stdexcept>
#include <string>

namespace pzstd {

// Coordinates graceful shutdown of the pzstd pipeline
class ErrorHolder {
    std::atomic<bool> error_;
    std::string message_;

 public:
    ErrorHolder() : error_(false) {
    }

    bool hasError() noexcept {
        return error_.load();
    }

    void setError(std::string message) noexcept {
        // Given multiple possibly concurrent calls, exactly one will ever succeed.
        bool expected = false;
        if (error_.compare_exchange_strong(expected, true)) {
            message_ = std::move(message);
        }
    }

    bool check(bool predicate, std::string message) noexcept {
        if (!predicate) {
            setError(std::move(message));
        }
        return !hasError();
    }

    std::string getError() noexcept {
        error_.store(false);
        return std::move(message_);
    }

    ~ErrorHolder() {
        assert(!hasError());
    }
};
}  // namespace pzstd
